Safety two-component detonator

ABSTRACT

There is a first detonator unit containing a first explosive mix component. This first unit has an inner and outer casing defining, respectively, first and second-stage detonating chambers, with a squib mounted in the first detonating chamber. There is a second unit which is a syringe containing a second explosive mix component which is injected into the detonator unit to mix with the first component to form an explosive liquid mix in the detonating unit.

United States Patent 1 Tlam [4 1 March 6, 1973 SAFETY TWO-COMPONENT DETONATOR [75] Inventor: Elvin W. Tlam, Redmond, Wash.

[73] Assignee: Explosives Corporation of America,

lssaquah, Wash.

22 Filed: Aug. 23, 1971 21 Appl.No.: 174,062

6/1 59 Davidson ..102/24R 5/1971 Macs ..l02/28R Primary Examiner-Verlin R. Pendegrass Attorney-John O. Graybeal et a1.

[5 7] ABSTRACT There is a first detonator unit containing a first explosive mix component. This first unit has an inner and outer casing defining, respectively, first and secondstage detonating chambers, with a squib mounted in the first detonating chamber. There is a second unit which is a syringe containing a second explosive mix component which is injected into the detonator unit to mix with the first component to form an explosive liquid mix in the detonating unit.

9 Claims, 2 Drawing Figures SAFETY TWO-COMPONENT DETONATOR BACKGROUND OF THE INVENTION A. Field of the Invention This invention relates to detonators, and more particularly to a detonator utilizing first and second explosive mix components which are combined at the site of use.

B. DESCRIPTION OF THE PRIOR ART Davidson, U.S. Pat. No. 2,892,377; Lewis, U.S. Pat. No. 2,929,325; and Macs, U.S. Pat. No. 3,580,171, all disclose devices in which first and second mix components are combined to form an explosive mixture.

Taylor et al., U.S. Pat. No. 2,424,374 and Swanson, U.S. Pat. No. 2,652,775 both disclose detonating devices where a first charge sets off a second charge.

SUMMARY OF THE INVENTION The present invention has a first detonating unit comprising a first inner casing defining a first-stage detonating chamber and an outer second casing enclosing the first casing and defining a main second-stage detonating chamber. A squib is located in the first chamber. There is a first explosive mix component positioned in the first unit.

There is a second unit which is a syringe containing a second liquid explosive mix component. The syringe is injected through a yielding closure of the first unit to inject the second liquid mix component into the first unit where it mixes with the first component to form a liquid explosive mix. The explosive mix is able to flow through passageways between the first and second chambers to substantially fill both the first and second chambers. Upon detonation of the squib, there is a three-stage reaction, the squib detonating to cause detonation of the explosive mixture in the first chamber, which in turn causes detonation of the mixture in the main chamber.

DESCRIPTION OF THE DRAWING FIG. 1 is an isometric view of the detonating unit of the present invention; and

FIG. 2 is a longitudinal sectional view of the detonating unit and a partial view of the second syringe unit of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention comprises two units: (a) a detonator unit 10, containing a first explosive mix component, and (b) a second syringe unit 12 containing a second explosive mix component.

The detonator unit comprises an outer cylindrical casing 14 in which is mounted concentrically an inner cylindrical casing 16. In the rear portion of the casing 16 is a conventional squib 18 to which are connected lead wires 20. The rear end of the outer casing 14 is I closed by a plug 22 having an inner plastic filler 24.

The inner casing 16 is closed at its front end by a plug 26 and defines a first-stage detonating chamber 28. The outer casing 14 is likewise closed at its front end by a plug 30 and defines a main second stage detonating chamber 32. Mounted in the forward plug 30 is a probe or cup 34 which is so configured and dimensioned as to fit into a conventional booster. This cup 34 defines a chamber 35 and has a rear opening 36 by which it communicates with the main second-stage chamber 32. The inner casing 16 has a plurality of side holes 38 through which the first chamber 28 communicates with the second chamber 32.

The second unit 12 is a syringe having a body 40 containing a second explosive mix component. There is a syringe needle 42 adapted to be pushed through the plastic filler 24 so that the second explosive mix component can be injected from the syringe 12 into the detonator unit 10.

As illustrated in FIG. 2, when the syringe needle 42 is pushed through the plastic filler 24, the end opening 44 of the needle 42 is disposed in a rear chamber 46 defined by the squib l8 and the plastic filler 24. The second liquid mix component passes through side holes 48 in the rear of the inner casing 16 and into the annular passageway 50 between the inner casing 16 and the outer casing 14. From the annular passageway 50, the second liquid component is able to flow into the first chamber 28 and the second chamber 32, where it mixes with the first liquid component already in the detonator unit 10 to form a liquid explosive mixture. The usual way of injecting the second mix component into the detonator unit 10 is to point the front end of the unit 10 downwardly, and then perform successive injection strokes, with each stroke injecting a portion of the second component and withdrawing some of the air from the unit 10 on each retraction. The quantities of the two explosive mix components are so selected that the unit 10 becomes substantially filled with the resultant explosive mixture.

A suitable composition for the first component is a solution of two parts hydrazine and one part diethylenediamine. This solution is by itself nondetonable and is a liquid. A suitable composition for the second explosive mix component is nitromethane, which is also normally liquid. The amounts of these two compositions are so selected that the ultimate mixture is 15 percent of the first component and percent of the second component, which is a detonable mixture.

When the squib 18 is fired, the inner casing 16 provides a sufficiently small confinement (i.e. the chamber 28) to cause detonation of that portion of the explosive mixture located in the first stage chamber 28. This in turn causes detonation of the explosive mixture in the main second chamber 32, annular passage 50 and the chamber 35. Thus, there is a three-stage detonation: (a) first the squib 15, (b) secondly the explosive mixture in the chamber 28, and (c) thirdly, the detonation in the larger chamber 32, the cup interior 35 and the annular passageway 50.

In the event that the squib 18 would detonate in its non-use condition (i.e., before the second explosive component is added to the detonator unit 10), since there is only a small amount of fluid in the detonator unit 10 (i.e., the first fluid component, which is only 15 percent of the total mixture), there is not a hydraulic rupture of the outer casing 10. Also, since the first mix component is by itself non-detonable, the only explos'ive force is that of the squib itself. The only effect is that the explosive force of the squib 18 will cause a small circumferential bulge in the inner and outer casings 16 and 14.

WHAT IS CLAIMED IS:

1. A two-part detonating assembly comprising:

a. a first detonating unit comprising;

l. a first inner casing defining a first-stage detonating chamber, an outer second casing enclosing said first casing and defining a main second-stage detonating chamber,

3. said inner casing having opening means interconnecting said first-stage and second-stage detonating chambers,

. squib means arranged relative to said first casing so that upon detonation its detonating force is directed to cause detonation in said first-stage chamber,

5. said inner and outer casing so arranged that a detonating force from said first-stage chamber is directed to cause detonation in said second chamber, and

a first explosive mix component located in said first detonating unit,

b. a second unit containing a second liquid explosive mix component to be combined with said first mix component to form a liquid explosive mixture in said first unit, and

c. transfer means associated with at least one of said units to transfer said second liquid component from the second unit into the first unit to be mixed with the first explosive mix component to form the liquid explosive mixture, whereby the explosive mixture is able to pass through said opening means so that said explosive mixture is located in both the first and second-stage chambers.

2. The apparatus as recited in claim 1, wherein said squib means is mounted within said inner casing.

3. The apparatus as recited in claim 1, wherein said outer casing is an elongate tubular member, and said inner casing is also an elongate tubular member located generally concentrically in said outer casing.

4. The apparatus as recited in claim 1, wherein said second unit comprises syringe means with an injection needle by which said second explosive mix component is inserted into said first unit.

5. The apparatus as recited in claim 1, wherein said first explosive mix component comprises hydrazine and diethylenediamine, and said second explosive mix component comprises nitromethane.

6. A field mix detonator, comprising:

a. a first inner casing defining a first-stage detonating chamber, an outer second casing enclosing said first casing and defining a main second-stage detonating chamber,

. said inner casing having opening means interconnecting said first-stage and second-stage detonating chambers,

. squib means arranged relative to said first casing so that upon detonation its detonating force is directed to cause detonation in said first-stage chamber,

e. said inner and outer casing so arranged that a detonating force from said first-stage chamber is directed to cause detonation in said second chamber, and

f. said unit being adapted to contain a first explosive mix component,

said unit having entry means by which a second explosive mix component can be introduced into said detonator to form with said first mix component a liquid explosive mixture which because of said opening means can occupy both the first and second chambers to provide detonating charges in each of said chambers.

7. The detonator as recited in claim 6, wherein said squib means is mounted within said inner casing.

8. The detonator as recited in claim 6, wherein said outer casing is an elongate tubular member, and said inner casing is also an elongate tubular member located generally concentrically in said outer casing.

9. The detonator as recited in claim 6 wherein said entry means comprises yielding closure means capable of being punctured and closing after said puncture. 

1. A two-part detonating assembly comprising: a. a first detonating unit comprising:
 1. a first inner casing defining a first-stage detonating chamber,
 2. an outer second casing enclosing said first casing and defining a main second-stage detonating chamber,
 2. The apparatus as recited in claim 1, wherein said squib means is mounted within said inner casing.
 3. The apparatus as recited in claim 1, wherein said outer casing is an elongate tubular member, and said inner casing is also an elongate tubular member located generally concentrically in said outer casing.
 3. said inner casing having opening means interconnecting said first-stage and second-stage detonating chambers,
 4. squib means arranged relative to said first casing so that upon detonation its detonating force is directed to cause detonation in said first-stage chamber,
 4. The apparatus as recited in claim 1, wherein said second unit comprises syringe means with an injection needle by which said second explosive mix component is inserted into said first unit.
 5. The apparatus as recited in claim 1, wherein said first explosive mix component comprises hydrazine and diethylenediamine, and said second explosive mix component comprises nitromethane.
 5. said inner and outer casing so arranged that a detonating force from said first-stage chamber is directed to cause detonation in said second chamber, and
 6. a first explosIve mix component located in said first detonating unit, b. a second unit containing a second liquid explosive mix component to be combined with said first mix component to form a liquid explosive mixture in said first unit, and c. transfer means associated with at least one of said units to transfer said second liquid component from the second unit into the first unit to be mixed with the first explosive mix component to form the liquid explosive mixture, whereby the explosive mixture is able to pass through said opening means so that said explosive mixture is located in both the first and second-stage chambers.
 6. A field mix detonator, comprising: a. a first inner casing defining a first-stage detonating chamber, b. an outer second casing enclosing said first casing and defining a main second-stage detonating chamber, c. said inner casing having opening means interconnecting said first-stage and second-stage detonating chambers, d. squib means arranged relative to said first casing so that upon detonation its detonating force is directed to cause detonation in said first-stage chamber, e. said inner and outer casing so arranged that a detonating force from said first-stage chamber is directed to cause detonation in said second chamber, and f. said unit being adapted to contain a first explosive mix component, g. said unit having entry means by which a second explosive mix component can be introduced into said detonator to form with said first mix component a liquid explosive mixture which because of said opening means can occupy both the first and second chambers to provide detonating charges in each of said chambers.
 7. The detonator as recited in claim 6, wherein said squib means is mounted within said inner casing.
 8. The detonator as recited in claim 6, wherein said outer casing is an elongate tubular member, and said inner casing is also an elongate tubular member located generally concentrically in said outer casing. 